Every now and then, we see steel pop back on the scene to take advantage of modern technologies, tube forming, and geometries. The latest is the all-new Mosaic RS-1, available in rim and disc brake variants. Made with Columbus Spirit HSS tubing, a tapered headtube and the classic threaded BB, they also throw back to the glory days with small touches like “star” cable port and bottle boss reinforcements. And more.

“Having a really solid steel road bike in our line-up really completes the models we offer,” said Aaron Barcheck, Mosaic Cycles founder and lead framebuilder. ““We’ve brought our own Mosaic perspective to the steel road bike; all the things you’d want out of a modern bike with the timeless ride qualities of a premium steel frameset.”

The RS-1 and RS-1d (“d” for “disc” brakes) are available for order now and will ship six weeks from order date, which is quick for a full custom frame. Each bike gets custom geometry based on the customer’s fit data, and custom oversized tube sets to match their size, weight and riding style.

2019 mosaic cycles rs-1d disc brake modern steel road bike 2019 mosaic cycles rs-1d disc brake modern steel road bike

What gives the bike its classic look are retro touches like the “star” mounting points, a braze-on front derailleur mount, and integrated rear derailleur hanger. And a threaded bottom bracket. Fortunately, since it’s steel, it’s easy enough to weld a new hanger on should you damage it in an accident.

Mosaic RS-1 rim brake bike details

mosaic rs-1 rim brake steel road bike with modern tubing

RS-1 frameset features for both models are:

  • Rider-specific custom geometry and tube set
  • Columbus Spirit HSS performance steel tubing
  • Chris King Dropset Headset
  • threaded 68mm bottom bracket
  • 27.2mm seatpost
  • tapered head tube
  • Braze-on front derailleur mount
  • Mechanical/ Di2/EPS/ Etap shifting available
  • Choice of Mosaic paint layouts and 45 stock colors
  • Six-week lead time
  • Price $6,000 $5,600 USD, complete bike $12,000 as shown

The rim brake version gets:

  • QR front and rear
  • Caliper brake mount
  • 28mm tire clearance
  • Enve Road tapered 1.5″ Carbon fork

Mosaic RS-1d disc brake bike details

Specs from the rim brake version carry over except for the following:

  • 142x12mm rear axle, 100x12mm rear axle
  • Flat mount brake front and rear
  • 30mm tire clearance
  • Columbus Futura Disc tapered 1.5″ Carbon fork

All bikes are available with custom paint from their in-house Spectrum Paint & Powder Works for an upcharge



  1. For the Mosaic RS-1d, is there a tube routing the rear hydraulic brake line from from entrance to frame exit? If so, how is that tube treated to resist rusting? Is there any treatment on the inside of Mosaic’s RS-1 and -1d frame tubes to resist rust?

    The tapered head tube is really nice touch, and at least for me, it works much better aesthetically than straight 44mm head tubes.

    • According to an Mosaic, all steel frames are treated with Frame Saver before they leave the factory. Tubes for internal routing are brass. I asked what the $6000 price tag includes and am awaiting a response.

    • Agreed. Nice production. Generally I’d expect a brand that can present itself that well also takes care of all the details when making the bikes.

    • The $6000 price needs a lot of clarification. Right now a Moots Vamoots RSL (titanium, of course) frame with fork is $4900. Maybe someone from Mosaic will chime in and clarify what that $6000 includes.

      • For $6k you get bragging rights that you’re a dentist and can afford to spend $6k on a frame that would be $4k for any other company.

        • If the steel frame was 500$ nobody would buy it, but paying 5000$ (or whatever it is the price over 1000$) for a steel frame would sound more ‘cool’ and some people will buy it because for some people it is not a matter of what you buy but how wcpensive you buy.

  2. “We’ve brought our own Mosaic pricing to the steel road bike”. Jeez, it is very pretty and all but you can get 2 or 3 really great steel frames for that price from less ‘exalted’ sources.

  3. I’ll buy a case of tissues for the next person to complain about the price. Not a box, a case.

    • Haha, jeez dude, $6000 for a bicycle is pretty ridiculous to the vast majority of bicycle riders out there. Must be a bitter pill to swallow when youre in your park ave penthouse!! <;0D

      • Frame, not bike. Doesn’t mean they’re not allowed to exist. Whining about the price of something you have no plans on purchasing seems a bit frivolous. You were doing the same thing a few days ago with the A/C Zig Zag, just a $1300 frame. Again, not in the market, just showed up to complain. Can’t afford $6k for a Mosaic, then get a Stelbel SB/03 that’s half the price. Oops, not buying that either, just more whining. As I see it you owe me a couple dimes for my ‘whine about the price of stuff you have no plans on buying retirement fund’.

  4. Erm looks like a sweet bike, the build this is questionable….
    Chain is on backwards with a joining pin, and quick link! Hahaha
    Hope the frame build quality is better than the mechanics

    • And that’s only in the short section of chain we can see! What if it has more joined pieces we can’t see. Reminds me of being broke and wondering if I could get away with making a whole chain out of the leftover links in my junk drawer.

  5. Looks sweet, great color
    Hope the frame build is better then the mechanics…
    Chain is on backwards, with joining pin and quick link haha

  6. If you read the article about the Hope HB.130 full suspension bike, made in England and the incredibly intricate detail, parts and work that went into it – it costs far, far, less than this simple steel frame. These are almost criminally overpriced; these guys are marketing geniuses if they can get people to cough up the absurd amount of cash they are asking for. You can get the sweetest ti frame in the world for less than this.

  7. People often complain about the ridiculously high bike prices. But the prices obviously work for at least a few companies. If you can find one rich idiot who will pay an extra 3 or 4 thousand dollars for star-shaped cable exit ports and a few other nice touches, then you have gone a long way to paying your business’s operating costs for the month. A few companies, like Enve, have actually succeeded at playing this game for over a decade.

  8. Sooooooo, how is it different? Columbus tubing, Paragon dropouts, all the same braze-ons that any other framebuilder can get. Regardless of the price, it seems like a run of the mill steel frame. Considering that it is stratospherically expensive, one would think they’d put a little more effort in. A Stinner is essentially the same thing, but half the price. A Speedvagen is closer to the price, but hella custom everything. Maybe I’m missing something?

    • Yes you’re missing the ‘mystique’ that lets everyone know that you are a 1%er because you have an obscenely overpriced bike. Not some shmo who has a Curtlo, for example, with easily equal or better craftsmanship, tubing and custom geometry, but costs only a third as much.

  9. “Fortunately, since it’s steel, it’s easy enough to weld a new hanger on should you damage it in an accident”.

    … … … …i’d imagine the down to earth fella/madam who buys one of these frames and rips the hanger off would probably want the paint to be retouched in a matching color… Is that also “easy enough”??

  10. For that price you’d think they’d have the attention to detail to take a few minutes and file that blob of silver off the Di2 reinforcement on the chainstay.

  11. Amazing the lengths and expense people will go to for that last .5% of whatever – style, craftsmanship, fit etc. In the meantime, 99% of these custom steel frames will use a carbon fork, because they are the best performers. Never mind the fact that what’s good for the goose is good for the gander, and you can have quite a nice carbon frames for $2K (or less) that will do everything this frame will do, provided you are willing to do a little research to ID the frame that will fit correctly. But hey, if Mosaic can sell ’em, more power to ’em.

    • If you do that then your bike is no longer real because only steel is real. Funny that you brought up Vanilla. Another silly hyped steel frame made with plain Jane tubing (nothing special at all, and cute cut out polished dropouts). But what fork do all their “steel is real” Vanilla and Speedvagen bikes run? Yep, carbon fiber. For $6k I can get a BMC Time or Roadmachine frameset (one of many examples) of which either are a good deal lighter, much better performing, each with infinitely cleaner (nearly invisible) front end cable routing, and still have money left over to pay for the bulk of a Di2 or SRAM wireless group. The $6k price is good for a couple chuckles though. Heck, a Cervelo R5 frameset at $1800 less would blow the doors off this steel frame performance wise and make it look like a dinosaur. Bingham full custom titanium for $2k less just another giggles example. LOL, good pricing comedy though for sure. 🙂

  12. Just gonna say it – Taiwan mass welds are looking better than US boutique welds these days. Speedvagen welds have gone down hill, Wraith looked like shit, these look like shit. I bought a steel kona a few years ago – GORGEOUS welds. Taiwan

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